20 August 1986 New Projection Lenses For Optical Stepper
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Optical step and repeat systems are now considered to be the major exposure equipment for the production of VLSI devices. Because of their high resolution and overlay accuracy, they are being used extensively to produce high density MOS memories, but are expected to be used increasingly in the production of custom LSI and discrete IC's, as well as highly integrated future MOS memories with submicron design rules. Projection lenses for optical steppers are required to have a wide exposure field and high resolution. This, however, is a design dichotomy which is difficult to achieve simultaneously. One possibility is to have a wide exposure field lens, but with a moderate resolution, and another is to have a high resolution lens, but with a narrow exposure field. Recently several projection lenses have been developed at Nikon. One has an extremely wide exposure field in order to achieve a high throughput, and another has an extremely high resolution, but a smaller exposure field. In this paper, the performance and special features of these lenses will be discussed. Special emphasis will be placed on the performance of the high resolution lens for submicron lithography, and SEM resist profiles produced by these lenses will be shown.
© (1986) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kazuo Ushida, Kazuo Ushida, Masaomi Kameyama, Masaomi Kameyama, Satoru Anzai, Satoru Anzai, "New Projection Lenses For Optical Stepper", Proc. SPIE 0633, Optical Microlithography V, (20 August 1986); doi: 10.1117/12.963698; https://doi.org/10.1117/12.963698

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